diff --git a/Modules/_pickle.c b/Modules/_pickle.c
index 34ce38c..ba8962d 100644
--- a/Modules/_pickle.c
+++ b/Modules/_pickle.c
@@ -6804,7 +6804,7 @@
 
     self->stack = (Pdata *)Pdata_New();
     if (self->stack == NULL)
-        return 1;
+        return -1;
 
     self->memo_size = 32;
     self->memo = _Unpickler_NewMemo(self->memo_size);